[R-sig-Geo] sill not reaching 1 in a climatological variogram

[Edzer Pebesma]

On 05/02/2013 06:30 PM, subash wrote:
> Hi All,
> 
> I constructed a climatological variogram using 'gstat' package in R at daily
> scale using 2 monsoon(JJAS) data. The *exponential* model was with variogram
> parameters  
> 
> nugget - 0.04243
> psill - 0.96633
> Range - 16.88 Km
> 
> <http://r-sig-geo.2731867.n2.nabble.com/file/n7583465/climat_vario.png> 
> 
> I have couple of questions:
> 
> (1) Why is the psill not reaching 1, when the each day rain has been
> normalized?

total sill, i.e. psill + nugget are supposed to approach the variance of
the field; they seem to do so. I also believe that this only holds for
the ergodic case, where you would make your spatial domain infinite.

> (2) Why is there a dip in the variogram at 50Km?

I wouldn't see this as a structural property; consecutive sample
variogram estimates are dependent as they share the same observations
when forming pairs.

> 
> Your help will be highly appreciated.
> 
> Thanks & Regards
> Subash
> 
> 
> 
> 
> 
> 
> 
> --
> View this message in context: http://r-sig-geo.2731867.n2.nabble.com/sill-not-reaching-1-in-a-climatological-variogram-tp7583465.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
> 
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 

-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
83 33081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de